G-Banded Karyotype and Ideogram for the North Atlantic Right Whale (Eubalaena glacialis)

Abstract

Published cytogenetic data for extant cetacean species remain incomplete. In a review of the literature, we found karyotypic information for 6 of the 13 tentatively recognized species of the suborder Mysticeti (baleen whales). Among those yet to be described is the critically endangered North Atlantic right whale (Eubalaena glacialis). Herein, we describe and propose a first-generation G-banded karyotype and ideogram for this species (2n = 42), obtained from peripheral blood chromosome preparations from a stranded male calf. This information may prove useful for future genetic mapping projects and for interspecific and intraspecific genomic comparisons by techniques such as zoo-FISH.

Hybridization in the Cetacea: widespread occurrence and associated morphological, behavioral, and ecological factors

“…; Pause et al. ) were removed from the analyses. The Mantel test, Wilcoxon sum rank test and the PCA with all comparisons were performed twice for both all species comparisons and for species with 44 chromosomes: once with the raw similarity index, and again with the similarity index weighed according to expert opinion.…”

“…Assuming that a different number of chromosomes or chromosomal arrangement will prevent or strongly deter hybridization (Dobzhansky 1935), we repeated the analyses using only cetaceans with the same chromosomal number. Therefore, those 26 species (beaked whales, right whales and sperm whales) with 42 chromosomes ( Arnason and Benirschke 1973;Arnason et al 1977;Pause et al 2006) were removed from the analyses. The Mantel test, Wilcoxon sum rank test and the PCA with all comparisons were performed twice for both all species comparisons and for species with 44 chromosomes: once with the raw similarity index, and again with the similarity index weighed according to expert opinion.…”

“…; Pause et al. ). The proportion of oceanic cetaceans with 44 chromosomes in which hybridization is known to occur is 50% (Tables and ).…”

“…Cetaceans are a relatively recent radiation; most of the species diversity has arisen in the past 10 million years (McGowen et al 2009;Slater et al 2010). The recent radiation, combined with an apparently slow rate of molecular evolution (Hoelzel et al 1991;Schl€ otterer et al 1991), likely accounts for common chromosome number (2n = 44) and karyotic arrangement present in most cetaceans ( Arnason and Benirschke 1973;Arnason et al 1977;Pause et al 2006). The proportion of oceanic cetaceans with 44 chromosomes in which hybridization is known to occur is 50% (Tables 1 and 2).…”

The systematics of right whales (Mysticeti: Balaenidae)

“…Alternate character states were assessed from personal examination of specimens and/or published descriptions. Coloration, soft anatomical, and karyotypic characters were coded solely from the literature (Tomilin 1967,Árnason and Ledje 1992, Schaeff and Hamilton 1999, Werth 2000, Reeves et al 2002, Pause et al 2006.…”